| Obesity is a world-wide epidemic disease that correlates closely with manymetabolic abnormalities, such as type2diabetes and cardiovascular diseases. Duringthe initiation and progression of obesity, hypertrophic adipocytes secrete morechemotactic factors, which induce various inflammatory cells (such as macrophagesand mast cells, et al) infiltrate into adipose tissues and increased adipose tissueinflammation, then result in systemic and insulin resistance. Momordica charantia(bitter melon, BM) is a nutritious and healthy vegetable. The anti-diabetes andanti-obesity effect of BM have been demonstrated in a large number of studies,however, it is unclear whether BM could alleviate adipose tissue inflammation causedby obesity. The inflammatory mechanism study of BM improved obesity and diabetes,which would offer the theoretical direction for development and application offunctional food about BM.In this study, to test the effects of BM on diet-induced obesity and diabetes inmice, five-week-old male C57BL/6mice were fed with high fat diet (HFD) or HFDsupplemented with2%or5%BM, and the mice fed with low fat diet (LFD) or LFDcontained the same percent BM were used as control groups. The results showedthat increased trend in body weights, adipocyte sizes and insulin resistance wereattenuated sharply by BM in HFD fed mice, but BM had no effect on food intake ofmice. Histological staining and real-time PCR analysis demonstrated BM not onlyreduced macrophage and mast cell infiltration into adipose tissues, but alsomodified the M1/M2phenotype ratio of macrophages and pro-inflammatorycytokine monocyte chemotactic protein-1, leptin and interleukin-6and tumornecrosis factor-α, as well as anti-inflammation cytokine adiponectin expression inadipose tissue. And then, ELISA analysis showed BM-contained diets alsonormalized serum levels of these cytokines. Those results showed thatBM-contained diets could reduce obesity-associated adipose tissue and systeminflammation. Further mechanism study showed that BM-contained HFD couldenhance Akt signal and mRNA expression of glucose transporter-4and peroxisomeproliferator-activated receptor γ of adipose tissue in mice. Finally, we tested theeffect of BM-contained diet on performed obesity and diabetes. The results showed BM reverses diet-induced obesity and improved insulin resistance in mice.In summary, in concert with ameliorated HFD-induced obesity and diabetes, BMcould inhibits obesity-associated the increased adipocyte sizes and inflammatory cellnumbers, and reduced adipose tissue and system inflammation in mice. Themechanism of bitter melon improves HFD-induced obesity and diabetes may byreducing adipose tissue and system inflammation, and then BM-mediated reducedinflammation depression promoted Akt and PPARγ action in adipocytes, resulting inincreased tissue glucose intake. |
